Adhesive applicator for perfect bound books and method of applying adhesive

Abstract

An adhesive applicator is disclosed for the application of a hot melt adhesive to the spine of a book block so as to adhesively bind the book block to its respective cover so as to form a perfect bound book. The applicator has a heated head in which a small quantity of a hot melt adhesive sufficient to bind at least one book block to its cover is quickly heated to a temperature such that it may be applied to the spine. The head is brought into operative engagement with the spine and is moved with respect to the spine so that the melted adhesive forced (dispensed) out of the head onto the spine. This applicator is particularly well suited for use with print on demand book printing and binding apparatus. A method of applying the adhesive to the spine of a book block is also disclosed.

The invention claimed is: 
     
       1. Apparatus for applying adhesive to the spine of a book block so that said book block to have a cover adhesively bound thereto along said spine, said apparatus comprising a head, said book block and said head being movable relative to one another toward and away from one another between an adhesive applying position in which said head is in operative relation with said spine so as to apply said adhesive to said spine and a retracted position in which said head is clear of said spine and further being movable relative to one another along a path substantially parallel to said spine of said book block, said adhesive being a solid member when at room temperature, said head having at least one heater for heating said adhesive to a flowable state for application to said spine, a drive which feeds said solid adhesive member into said head so as to be heated to said flowable state within said head, and a pump for effecting the dispensing of flowable adhesive from said head thereby to apply said adhesive to said spine as said book block and said head are moved relative to one another along said path, wherein said head having an end face adapted for the application of said flowable adhesive to said spine when said book block spine and said head are in operative relation with one another and when said book block and said head are moved along said path, said head having a slot across said end face with one portion of said head on one side of said slot extending axially out beyond another portion of said end face on the opposite side of said slot, said one portion of said head end face leads said slot relative to said relative to the direction of relative movement between said spine and said head during application of adhesive so that said other portion of said head is stepped back from said spine, and wherein said slot is in communication with said flowable adhesive within said head such that upon dispensing of said flowable adhesive said step back of said other portion of said head determines the thickness of said adhesive applied to said spine, wherein said book blocks range between a minimum and a maximum thickness, wherein the length of said slot is such that said slot extends across substantially the thickness of a spine of said maximum thickness book block, and wherein said head is rotatable about a horizontal axis from a first position in which said slot is generally perpendicular to said spine to an angled position so as to accommodate book block thicknesses ranging between said maximum thickness and a minimum thickness. 
     
     
       2. Apparatus as set forth in  claim 1  wherein said head is spring biased to return to its said first position upon release from its angled position. 
     
     
       3. Apparatus as set forth in  claim 1  whereupon said spine having said adhesive applied thereto, said adhesive member is partially withdrawn from said head so as to terminate the flow of said flowable adhesive. 
     
     
       4. Apparatus as set forth in  claim 1  wherein said adhesive member constitutes said pump such that as said adhesive member is fed into a chamber so as to dispense said adhesive from said head. 
     
     
       5. Apparatus for applying adhesive to the spine of a book block for adhesively binding a cover to said book block where the thickness of said book block may vary within a limited range from a maximum thickness to a minimum thickness, and where said book block has a spine, said apparatus comprising:
 (a) a head having a chamber therein for containing a supply of adhesive sufficient to bind at least one of said book blocks to a cover, said head having an end face adapted to be in operative relation with said spine of a book block so as to apply said adhesive thereto; 
 (b) a heater for heating adhesive within said chamber to a temperature sufficient to effect application of said adhesive to the spine of said book block; 
 (c) an opening in said end face of said head with one portion of said head on one side of said opening extending axially out beyond another portion of said head on the opposite side of said opening for the application of said adhesive to the spine of said book block; 
 (d) said one portion of said head leads said opening with respect to the direction of relative movement between said book block and said head so that said other portion of said head end face is stepped back from the spine of said book block; 
 (e) said opening being in communication with the molten adhesive in said chamber; and 
 (f) a pump for dispensing molten adhesive from said chamber for application to said spine of said book block as said head and said book block are moved relative to one another; 
 (g) said head being rotatable about an axis substantially perpendicular to said spine of said book block between a first position in which said opening is oriented generally perpendicular to said spine and an angled position in which said opening is angled diagonally across said spine where said opening is of a length sufficient so as to extend across substantially the thickness of said spine of said maximum thickness book block so that adhesive may be applied to the spine of a book block having a thickness equal to said maximum thickness and so that with said head at said angled position, said opening extends diagonally across the spine of a book block having a thickness less than said maximum thickness. 
 
     
     
       6. Apparatus as set forth in  claims 5  wherein the distance that said one portion of said head extends axially out beyond said other portion of said head determines the thickness of said adhesive applied to said spine. 
     
     
       7. Apparatus as set forth in  claim 5  wherein said opening is a slot extending diametrically across the end face of said head and wherein said angled position of said slot ranges between about 0° and about 45° from said first position. 
     
     
       8. Apparatus as set forth  claim 5  wherein said solid adhesive member is an elongate member, and wherein said apparatus has a positive feed which advances said adhesives member to said head such that said adhesive member constitutes said pump. 
     
     
       9. Apparatus as set forth in  claim 8  wherein said positive feed comprises one or more drive members in driving engagement with said adhesive member so as to feed said adhesive member into said chamber at a rate sufficient to insure that said chamber has a sufficient supply of molten adhesive so that a sufficient quantity of said molten adhesive is dispensed from said chamber so as to apply said adhesive to said spine. 
     
     
       10. Apparatus as set forth in  claim 8  wherein said positive feed is further operable so as to at least partially withdraw said adhesive member from said chamber so as to effect termination of dispensing of adhesive. 
     
     
       11. Apparatus as set forth in  claim 5  wherein said head has a first gage pin disposed adjacent one end of said slot, said first gage pin being positioned proximate one surface of said book block adjacent said spine as said book block and said head are brought into engagement with one another. 
     
     
       12. Apparatus as set forth in  claim 10  wherein said head has a second gage pin adjacent the opposite end of said slot with the distance between said gage pins being somewhat greater than said maximum thickness of the thickest book block within said limited range of thicknesses of said book blocks. 
     
     
       13. Apparatus as set forth in  claim 11  wherein said opening is a slot extending diametrically across the end face of said head, and wherein upon rotation of said head from its first to said angled position, said first gage pin is moved into engagement said one surface of said book block and said second gage pin is moved into engagement with the other surface of said book block with said slot angling diagonally across the thickness of said spine for the application of adhesive thereto. 
     
     
       14. Apparatus as set forth in  claim 13  wherein said heater is comprised of a pair of rod electric heaters, 
     
     
       15. Apparatus as set forth in  claim 14  wherein said rod heaters are spaced from one another and each of said rod heaters has an outer end portion extending out beyond the end face of said head and thus constituting said gage pins. 
     
     
       16. Apparatus as set forth in  claim 5  wherein with a book block in register with said end face of said head, said head being movable in a direction parallel to said axis toward and away from said spine of said book block between a retracted position in which said end face is clear of the spine of the book block and an operative position in which said one portion of said end face of said head is in operative engagement with said spine. 
     
     
       17. Apparatus as set forth in  claim 16  further comprising a motor operatively connected to said head for moving said head between its said retracted and operative positions. 
     
     
       18. Apparatus as set forth in  claim 5  further comprising a programmable controller for controlling operation of said apparatus, wherein data regarding the thickness and length of said spine is supplied to said controller, the latter determining the amount of adhesive to be applied to said spine of said book block in proportion to the thickness and length of said spine, said controller effecting the feeding of said adhesive member into said chamber so as to dispense a quantity of said adhesive so that said adhesive will be substantially uniformly applied to said spine upon relative movement of said book block and said head. 
     
     
       19. Apparatus as set forth in  claim 18  wherein said controller effects the axial movement of said head from said retracted position to said operative position, effects said relative movement of said applicator and said book block along said patent, and effects the dispensing of adhesive from said head onto said spine. 
     
     
       20. Apparatus as set forth in  claim 19  wherein said supply of adhesive is in the form of an elongate adhesive member which is solid at room temperature, said apparatus having a positive feed which advances said adhesive member into said chamber in said head, said positive feed being under the control of said controller for effecting dispensing melted adhesive from said head to said opening and onto said spine. 
     
     
       21. Apparatus as set forth in  claim 20  wherein said positive feed comprises at least one drive member in engagement with said adhesive member so as to feed said adhesive member into said chamber to be melted therein. 
     
     
       22. Apparatus as set forth in  claim 21  wherein upon completion of application of said adhesive to said spine of said book block, said adhesive member is partially withdrawn from said head thereby to terminate the flow of adhesive from said head. 
     
     
       23. Apparatus as set forth in  claim 18  wherein said opening is a slot extending diametrically across the end face of said head, and wherein said apparatus further comprises a motor under the control of said controller for rotating said head from said initial position to an angled position with respect to said spine such that said slot extends diagonally across said spine so that said slot is fully covered by said spine. 
     
     
       24. Apparatus as set forth in  claim 23  wherein said head has a first gage pin adjacent one end of said slot for engaging one face of said book block proximate said spine when said head is rotated to its operative position. 
     
     
       25. Apparatus as set forth in  claim 24  wherein said head has a second gage pin adjacent the other end of said slot for engaging the other face of said book block proximate said spine when said head is rotated to its operative position. 
     
     
       26. Apparatus as set forth in  claim 18  wherein said head is mounted for movement along a path substantially parallel to said spine of said book so as to apply said adhesive to said spine. 
     
     
       27. Apparatus as set forth in  claim 26  wherein said head is mounted on one or more rails extending substantially parallel to said spine of said book. 
     
     
       28. Apparatus as set forth in  claim 18  further comprising an actuator for application of said adhesive to said spine of said book block, said actuator being under the control of said controller. 
     
     
       29. Apparatus as set forth in  claim 18  wherein said supply of adhesive is in the form of an elongate adhesive member which is a solid at room temperature, said apparatus having a positive feed which advances said adhesive member to said heater, said positive feed being under the control of said controller for advancing an amount of said adhesive member into said chamber and for dispensing adhesive from said head and onto said spine. 
     
     
       30. Apparatus as set forth in  claim 29  further comprising a drive wheel in gripping engagement with said adhesive member, said drive wheel being driven by a motor under the control of said controller. 
     
     
       31. Apparatus as set forth in  claim 30  wherein a gear train is interposed between said motor and said drive wheel. 
     
     
       32. Apparatus as set forth in  claim 29  whereupon the completion of dispensing of said adhesive, said elongate adhesive member being partially withdrawn from said head so as to terminate the dispensing of melted adhesive from said head. 
     
     
       33. Apparatus as set forth in  claim 29  wherein said heater is capable of melting said adhesive member fed into said head in a time so as to insure that there is a sufficient supply of melted adhesive in said head for the binding of the next book block to be bound. 
     
     
       34. Apparatus for applying adhesive to the spine of a book block of a book so that said book block may have a cover adhesively bound thereto along said spine, said book block having its spine exposed, said apparatus comprising a head, said book block and said head being movable relative to one another toward and away from one another between an adhesive applying position in which said head is in operative relation with said spine so as to apply said adhesive to said spine and a retracted position in which said head is clear of said spine and being movable relative to one another along a path substantially parallel to said spine of said book block, a heater for heating said adhesive to a flowable state for application to said spine, said adhesive being a solid member when at room temperature, and a dispenser for selectively dispensing adhesive from said head so as to apply said adhesive to said spine as said book block and said head are moved relative to one another along said path, wherein said heater heats said head to an elevated temperature, and wherein when said head and said book block are in said adhesive applying position, said heated head at least in part heats said spine so as to result in an improved wetting of the adhesive as the adhesive is applied by the head to the spine.